1. Field of the Invention
The present invention relates to a steerable balloon catheter, and more particularly to a balloon on a bi-directional steerable guidewire having a tip which may be very precisely “steered” and deflected. The guidewire supported balloon is particularly suitable for insertion into a vessel of the body and may be used for angioplasty and/or for placement of a stent within the vessel.
2. Description of the Prior Art
For many years balloons have been mounted on guidewires having a core wire with the distal end being tapered and with a coil spring mounted on the tapered distal end. These guidewires have been used to support and facilitate the insertion of a balloon into a vessel of the body. Generally, the guidewire supported balloon is inserted through a guiding catheter is then moved through the vessel until the balloon is positioned at a desired location.
While most guidewires used to support balloons do not include a mechanism for deflecting or “steering” the tip of the guidewire, it is very desirable to provide tip steering in order to facilitate movement of the balloon through the tortuous vessels of the body. There are many patents directed toward different mechanisms for deflecting the distal tip of a guidewire in order to steer the guidewire. Examples of such guidewires are disclosed in the following patents: U.S. Pat. No. 4,815,478 to Maurice Buchbinder, et al., U.S. Pat. No. 4,813,434 to Maurice Buchbinder, et al., U.S. Pat. No. 5,037,391 to Julius G. Hammerslag, et al., U.S. Pat. No. 5,203,772 to Gary R. Hammerslag, et al., U.S. Pat. No. 6,146,338 to Kenneth C. Gardeski, et al., U.S. Pat. No. 6,126,649 to Robert A. VanTassel, et al., U.S. Pat. No. 6,059,739 to James C. Baumann and U.S. Pat. No. 5,372,587 to Julius G. Hammerslag, et al. U.S. Pat. No. 4,940,062 to Hilary J. Hampton, et al., discloses a balloon catheter having a steerable tip section. All of the above-identified patents are incorporated herein by reference.
While each of this group of patents disclose guidewires which could be used to support a balloon and each having some degree of steerability, there is a need to have a guidewire with very precise “steering” through a vessel of the body. More particularly, there is an important need for a very small diameter guidewire supported balloon having a distal tip which may be rotated and then deflected very precisely to enhance “steerability.”